Dr. Frank Lin, a scientist at Johns Hopkins University, and some other colleagues of his, have found a strong correlation between hearing loss and the contraction of dementia at an old age. 639 subjects, part of the Baltimore Longitudinal Study of Aging, have been routinely observed for the last 18 years. The study showed that the individuals who developed a hearing problem, or had one from birth, were much more likely to contract dementia as they aged.
The study categorized the hearing losses according to severity, with categories of none, mild, moderate, and severe. The data showed that individuals with mild hearing loss are twice as likely to contract dementia as somebody with no hearing problem, individuals with moderate loss are three times as likely, and those with severe loss are up to five times as likely to contract dementia.
Dr. Lin says the correlation is due to "cognitive load". Simply put, when someone has a hearing issue, the fewer words they are able to make out can cause the brain to be so busy translating those sounds into words that it has trouble having time to come up with a response. Social isolation due to the hearing loss may also be a reason for the contractions of dementia.
NOS Themes:
- science is collaborative
- role of curiosity and motivation
- science is based on evidence
- study is subject to debate and tentative
I read a similar article on this, and in addition to "social isolation", some underlying brain damage that leads to both hearing and cognitive decline was also given as an explanation. My grandmother suffers from dementia, so I find this article particularly interesting. I also think it's worth noting that "those who suffered hearing loss took 7.7 years to show mental decline, vs. 10.9 years for those with healthy hearing" according to the study cited.
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